Does Blender work in Windows 10?
Yes. Blender 2.75a works in Windows 10. 

But I had some trouble making it work. After the upgrade from W8.1 to W10 it didn't work, but it was a problem of the new windows not having the correct drivers. 

I didn't have to spend much time working it out. Windows 10 did, after some time and a few reboots, offer to install the correct drivers. That fixed most of the problems, including the usual trouble with hardware controls in laptops. 

So, if you are upgrading to Windows 10, you might have some problems, but Blender will work well once your computer has Windows properly installed. At least it does with my Hardware.